1. Field of the Invention
The invention relates in general to conveyors and in particular to a new and useful single-chain scraper conveyor comprising flights which are secured to an endless chain, and a conveyor trough with trough lengths bent to circular segments, in which, in a zone of a curved path, the radially extending flights of the advancing and return sides of the chain apply by their inside ends tangentially against the circumferential portion of a deflector wheel which extends in the plane of movement of the flights and over the entire length of the curved path and projects into the conveyor trough through an aperture provided in the side wall of the trough.
2. Description of the Prior Art
There is known a single-chain scraper conveyor in which the deflector wheel is provided on its circumference with a trough-shaped recess for advancing and return sides of the chain, engaging over the adjacent ends of the flights. While the trough-shaped recess fixes the position of the adjacent flight ends in the vertical plane, the static friction between the adjacent flight ends and the trough-shaped recess, caused by the high radial contact pressure, tends to retain the adjacent flight ends, within the range of the curved path, in their contact positions. With regard to the centrally applied chain, however, this results in an additional advance of the free ends of the flights on the outside of the curved path, through an angle corresponding to the path length difference between the free ends and the inside ends of the flights. That is, while moving through the curved path, the free ends of the flights must cover a longer distance than the inside flight ends. The same analogously holds for the chain itself and the central portion of the flights. Taking into account that the flights enter and leave the curved-path zone in an exactly radial position, this additional advance of the free ends of the flights must be compensated. This is done in a jerky advance motion of the inside ends of the flights, compensating for the path-length difference between the two ends. The jerky advance of the inside flight ends takes place as soon as the tensional forces acting centrally on the chain and the retaining forces on the inside flight ends resulting therefrom increase to an extent such that they exceed the static friction between the respective inside ends of the flights and the recess. This results in periodical chain loads by accumulated tensional and bending forces and subsequent sudden tension releases. Thereby, and by the fact that within the curved-path range and up to the compensation for the path-length difference the chain, ahead of and behind the flight, is stressed at different angles and the life of the chain is considerably reduced. In addition, the jerky advance of the inside ends of the flights leads to an increased wear and may cause catapulting of stones. All these drawbacks are to be eliminated by the invention.